The use of iron electrodes in storage batteries, metal/air batteries or cells and the like is old and well known. For example, the nickel-iron-alkaline cell, or Edison cell, comprises a nickel oxide positive plate, an iron negative plate, and a potassium or lithium hydroxide electrolyte. The iron electrode of the commerical Edison cell typically consists of perforated tubes or plates of nickel containing iron oxide. The tubes are generally supported in a grid structure.
In recent years, however, substantial improvements have been made in the performance of iron electrodes by depositing activated iron oxide into small pockets or grids which are formed by sintered nickel fiber mats or in pockets formed by nickel-plated steel wool fibers. The performance obtained from iron electrodes fabricated in this manner represents a substantial improvement over commercially available iron electrodes as embodied in the Edison cell.
Notwithstanding the satisfactory performance obtained from iron electrodes fabricated with sintered nickel grids, they have a number of inherent disadvantages. One of the primary disadvantages is that they are relatively expensive. Not only are the nickel or nickel-plated sintered fiber mats expensive, but the processing required to load the iron oxide into the pockets formed within the mats is costly. Furthermore, the weight of the nickel fiber mat is sufficiently high to provide low weight coefficiencies for the electrode allowing only limited current drains.
Accordingly, it is an object of the present invention to provide a process for the preparation of iron electrodes in which performance characteristics of the iron electrode is at least as good as that of the fiber grid iron electrodes, but in which a substantial reduction in weight can be achieved. It is also an object of the invention to provide a process for the manufacture of iron electrodes which is substantially less expensive than conventional processing techniques.